Superior Strength and Electrical Conductivity Synergy of Cold-Drawn Al-Mg-Si-Ce-Cu Wires Produced by Continuous Casting and Rolling

Al-Mg-Si aluminum wires for overhead power transmission have extensive applications in industry and daily life. Herein, superior strength and electrical conductivity combinations in the aged cold-drawn Al-Mg-Si-Ce-Cu wires fabricated by continuous casting and rolling are achieved. The cold-drawn wires exhibit high strength and electrical conductivity combinations of 383 +/- 2 MPa, 51.16 +/- 0.23% International Annealed Copper Standard (IACS); 373 +/- 3 MPa, 51.98 +/- 0.25%; and 357 +/- 3 MPa, 53.16 +/- 0.11% IACS, respectively, when aged at 160, 170, or 180 degrees C for 24 h. Subgrain boundaries are introduced into alloys by continuous casting and rolling and cold drawing, causing significant lattice distortion within the grains and providing sites for the nucleation of precipitates. Moreover, high-angle-annular dark-field scanning transmission electron microscopy and density functional theory results show that Ce atoms could enter the lattice of beta" and replace the Si3 sites, which is energetically preferred. The underlying mechanisms for achieving superior strength-electrical conductivity combination are to introduce subgrain boundaries via continuous casting and rolling and cold drawing for promoting the transformation of solid solution atoms to finely dispersed precipitates, which significantly reduces the scattering of electrons and hence improves the electrical conductivity. This work provides a new strategy for designing high-strength and high-conductivity aluminum alloy wire conductors. Herein, the authors produce the superior strength and electrical conductivity synergy of cold-drawn Al-Mg-Si-Ce-Cu wires by continuous casting and rolling. The cold-drawn Al-0.5Mg-1Si-0.3Ce-0.2Cu wires exhibit remarkable combinations of strength and electrical conductivity of 357 +/- 3 MPa and 53.16 +/- 0.11% International Annealed Copper Standard, when aged at 180 degrees C for 24 h. The underlying mechanisms are also revealed.image (c) 2024 WILEY-VCH GmbH